In a recording type information recording medium, such as a CD-R (Compact Disc-Recordable), a DVD-R, a DVD-RW, and a DVD+R, what is general is an information recording medium, such as an optical disc, on which a recording layer is laminated or bonded on a substrate. Moreover, on an information recording apparatus, such as a DVD recorder, which performs recording on such an optical disc, laser light for recording is focused on the recording layer, to thereby record information in an irreversible change recording method by heat or the like, or in a rewritable method by phase change or the like.
Moreover, as a method of managing data recorded on the recording type information recording medium (e.g. a method of specifying the recording position of the data or the like), a file system is generally used. For example, in a DVD, UDF (Universal Disk Format) is defined as the standard file system. In particular, in write-once type media (write once disc), such as e.g. a DVD-R, on which writing is allowed only once, there is a method of managing a file on the basis of UDF VP (UDF Virtual Partition) using so-called VAT (Virtual Allocation Table). The management method using the VAT is used mainly in rewriting file system information about a file recorded on a write-once type optical disc.
On the other hand, in the latest personal computer using Windows XP (registered mark), which is the latest standard OS (Operation System), UDF VAT and UDF VP can be recognized and read. On the other hand, electronic equipment which is widely distributed in the market, such as an old version of Windows (registered mark), MAC OS (registered mark), a commercially available DVD player, portable DVD CE (Compact Edition) equipment, and on-vehicle DVD equipment, does not correspond to UDF VAT and UDF VP, so that the electronic equipment cannot read them.
Thus, the electronic equipment (a DVD Video Recorder) that performs recording on the write-once type media, such as a DVD-R, or the like prepares a compatible file system, such as ISO/UDF Bridge file system, which has compatibility with read-only media, such as a CD-ROM and a DVD-ROM, by conversion from the latest standard file system, such as UDF Virtual Partition, and records it onto the write-once type media. As a result, even in the aforementioned electronic equipment which is widely distributed in the market, the compatibility can be ensured to perform the reproduction of the write-once type media. Incidentally, in the present invention, converting the file system, such as UDF Virtual Partition, to the compatible file system, such as ISO/UDF Bridge file system, is referred to as “providing compatibility” or “performing a compatibility process”, as occasion demands, wherein the compatible file system is provided with a plurality of file systems, such as ISO 9660 file system, ISO 9660 Joliet extension file system, and UDF 1.02 file system.    Patent document 1: Japanese Patent Kohyo NO. 2000-503446    Patent document 2: Japanese Patent Application Laid Open NO. 2001-23237    Patent document 3: Japanese Patent Application Laid Open NO. 2002-150706